One approach to overcome the limitations of a conventional front-contacted solar cell is to move both the p-n junction and the back surface field (BSF) to the rear side of the solar cell. This architecture is called a back contact solar cell. By moving both the p-n junction and the BSF to the rear, all metallization required to extract generated carriers is also moved to the rear side. The front, sunward side is therefore free from shading losses, enabling higher short circuit current and thus efficiency. Another advantage of having metal contacts on the rear side is that the metal geometry is no longer constrained to minimize shading losses, allowing for wider metal contacts which reduce resistive losses. Having all metal contacts on the back side also has the added benefit of simplifying integration of solar cells into a module.
Various methods have been suggested with regard to the manufacturing process of back contact cells. Such methods are described in U.S. Pat. No. 9,048,374 directed to the manufacturing process of interdigitated back contact (IBC) solar cells; Andreas Halm et al, “The zebra cell concept—large area N-type interdigitated back contact solar cells and one-cell modules fabricated using standard industrial processing equipment”, 27th European Photovoltaic Solar Energy Conference and Exhibition, page 567-570 (2012); and Ilkay Cesar et al, “Mercury: A back junction back contact front floating emitter cell with novel design for high efficiency and simplified processing” Energy Procedia 55 (2014) 633-642.